this module can be set to a transmitter or receiver, transmitter could pairing with receiver , receiver and receiver or transmitter and transmitter can't communication between, receiver could pairing with computers and cell phone bluetooth , when buying, the default for receiver.

No "Automatically prevent power supply peversing func", so please correctly connect power supplyWe advise to install "Bluetooth master module"The "State" is output foot for LED status, when bluetooth "Unconnected", output "Pulse" ; when bluetooth "connected", output "High level", we can determine the states from "MCU"If only the board , No any "Bluetooth Function .